| Autor: |
Lin Peng, Mao Yuzhu, G., Hong Chaosheng, G., Pavese, Franco, Peroni, Ilaria, Head, David, Rusby, Richard |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2003, Vol. 684 Issue 1, p191-196, 6p |
| Abstrakt: |
This paper presents lambda-point measurements obtained at CL, IMGC, and NPL in the past two years using sealed cells made at CL. The cells consist of two chambers containing liquid helium, separated by a stainless-steel capillary. When the He I/He II interface is located in the capillary, the large thermal conductivity of He II ensures that the lambda temperature Tλ is established in the top chamber. Heat flows change the position of the interface, but have only a small effect on the temperature of the top chamber. Because of the self-adjusting effect of the He I column within the capillary, the lambda transition temperature plateau was recorded in the top chamber for many hours with a fluctuation of 3.2 μK. The temperature of the lambda transition at zero heat flow is determined by measuring the temperature at several heat flows and extrapolating to zero. The best realizations of Tλ were made at NPL with a standard deviation of 5.8 μK, and the effect of the finite conductivity of He II was observed for the first time in this cell. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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